Drip chamber assembly that functions irrespective of orientation

ABSTRACT

A drip chamber assembly that functions irrespective of its orientation and in the presence of increased internal pressure is provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.62/093,088, filed on Dec. 17, 2014, entitled “Drip Chamber Assembly ThatFunctions Irrespective of Orientation,” which is hereby expresslyincorporated by reference into the present application.

FIELD OF THE INVENTION

The present invention relates to the field of medicine, and moreparticularly, to medical devices for fluid delivery to patients or totarget devices. More specifically, the invention relates to a dripchamber assembly to be used as part of an infusion apparatus.

BACKGROUND

Intravenous (IV) therapy allows fluids to be infused directly into avein. Compared to other fluid administration methods, IV therapy is oneof the most efficient ways to deliver fluids to a patient. For infusion,a drip chamber is typically connected to the bottom of an IV bagcontacting the fluid to be administered. Tubing is connected to thebottom of the drip chamber and can include means for intravenouslyinserting a needle or port though which the fluid is administered. Thedrip chamber permits gas (such as air) to escape from the fluid beforethe fluid enters a patient. In a patient, the inadvertent introductionof a gas bubble into a vein can result in what is called an embolism,which can in turn produce a blockage in a blood vessel. Many examples ofthe use of drip chambers by medical personnel to regulate the flow ofintravenous fluids to a patient are known and disclosed in U.S. patents(see, e.g., U.S. Pat. Nos. 4,395,260, 4,601,712 and 5,776,109).

The use of a drip chamber also allows an estimate of the rate at whichfluids are administered. For a fluid of a given viscosity, drips from ahole of known size will be of nearly identical volume and the number ofdrips in a minute can be counted. The rate of flow can be controlled,e.g., by a clamp on the infusion tubing. The clamp affects theresistance to flow, and provides increased pressure within the cup.However, other sources of resistance (e.g., whether the patient's veininto which fluids are being delivered is kinked or compressed by thepatient's position) cannot be so directly controlled, and a change inposition may change the rate of flow leading inadvertently to either toorapid or too slow infusion. In problematic cases such as this, aninfusion pump or pressurized infuser may be used which gives a moreaccurate measurement of flow rate.

In order to minimize the possibility of introducing gas bubbles, andmaintain the correct “head height” (typically 39″ to 42″) for gravityinfusion, plus avoid backward flow through the line, it is preferable tokeep the drip chamber and infusion apparatus elevated over the patient.However, in emergency situations it is not always possible and/orconvenient to keep the drip chamber and infusion apparatus elevated overthe patient. Another problem that can occur is that the drip chamber canopen up when under pressure resulting from resistance provided byclamping to control drip rate or by vein compression.

Therefore, there is a need for a drip cup assembly which can functionconsistently, from any position, in any situation, and which canwithstand increased internal pressure.

SUMMARY OF THE INVENTION

It has been discovered that a drip chamber assembly is able to hold itsconnection under pressure when its components utilize complementarylocking portions.

This discovery has been exploited to provide, in part, a drip chamberassembly that includes an approximately half-spherical drip chamberbottom, an approximately half-spherical drip chamber top, fluid deliverytubes, and a drip chamber cap. The drip chamber bottom is configured forreceiving and interlocking with the drip chamber top having a raisedfill line. The interlocking of the half spheres allows the drip chamberto remain joined together even when substantial force is applied withinthe drip chamber assembly. The interlocking uses a circular portion onthe lower portion of the drip chamber top as the male member. The malemember is positioned between an outer an inner circular portion (femalemember) of the upper portion of the drip chamber bottom.

The assembly functions irrespective of its orientation. The fluid thatpasses through the assembly can be sent directly to a patient oralternatively to a target device. The assembly can be used with a cuffthat holds the fluids to be delivered and can use a gas cartridge forpressurizing the cuff, which in turn pressurizes the source of thefluids to provide for rapid delivery or infusion.

In addition, the disclosure provides a drip cup assembly with chambercaps that have outlets with different cross sectional areas. As thecross sectional area of the outlet decreases the number of drops pervolume of fluid increases.

Other aspects and advantages of the invention will be apparent from thefollowing description and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects of the present disclosure, the variousfeatures thereof, as well as the disclosure itself may be more fullyunderstood from the following description, when read together with theaccompanying drawings in which:

FIG. 1 is a schematic representation of a representative drip chamberassembly;

FIG. 2 is a schematic representation of a drip chamber top and bottom;

FIG. 3 is a schematic representation of male and female members of thedrip chamber top and bottom;

FIG. 4 is a schematic representation of a cuff and carbon dioxidecartridge for use with the drip cup assembly;

FIG. 5 is a schematic representation of the portion of the drip chamberassembly that gets inserted into an IV bag; and

FIG. 6 is a photographic representation of a representative drip chamberassembly with accessories.

DETAILED DESCRIPTION

The disclosures of these patents, patent applications, and publicationsin their entireties are hereby incorporated by reference into thisapplication in order to more fully describe the state of the art asknown to those skilled therein as of the date of the invention describedand claimed herein. The instant disclosure will govern in the instancethat there is any inconsistency between the patents, patentapplications, and publications and this disclosure.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this disclosure belongs. The initial definitionprovided for a group or term herein applies to that group or termthroughout the present specification individually or as part of anothergroup, unless otherwise indicated.

Drip Cup Assembly

The present disclosure provides a drip chamber assembly useful fordelivery of fluids either to a patient via intravenous administration orto a target device, both of which benefit from delivery of air-freefluids. The drip chamber of the present disclosure has a sphericaldesign that makes this device an “all position drip chamber” (APDC).This drip chamber prevents air from entering the fluids that aredelivered to a patient or target device irrespective of the orientationof the drip chamber assembly. With regard to IV delivery, this featureis useful, e.g., when there is no room and/or time to elevate the fluidsor this not sufficient personnel present to hold the fluids over apatient. An advantage of the APDC is that the spherical shape allows forthe entire IV tube set up to be stored or transported in any position.

In some cases, the APDC is used to deliver a fluid to a target device.The target device can, for example, be an intermediate measuringcontainer. Such a measuring container can include a motor and controllerfor moving a syringe to deliver the desired amount of fluid.Alternatively, the target device can be some sort of processing devicein which further adjustments are made to the fluid before or instead ofbeing delivered to a patient.

whereas a conventional drip chambers needs to be orientated in thevertical position. The APDC can be used anywhere air or gas needs to beremoved from flowing liquid. The APDC incorporates novel closurefeatures to prevent excess pressure within the device from separatingthe assembly device into its component parts. In addition, the APDC caninclude a fill line for correct fluid measurement. The fill line canoptionally be raised internally and externally, allowing the personadministering treatment to the patient or administering fluids to atarget device to feel the line. Representative, non-limiting fluidswhich can be delivered to a patient or target device include glucosesolutions, saline solutions, medications in liquid form, aqueousphysiologically-acceptable fluids, and blood or plasma.

Referring to FIG. 1, in one aspect, the present disclosure is directedto a drip chamber assembly (2) that includes a joined drip chamber (4)(i.e., joined from a drip chamber bottom and top (see FIG. 2 and FIG.3)) and a drip chamber cap (6). The joined drip chamber includes a firstdistal inlet (8) engaged with the drip chamber cap and a first proximaloutlet (10) configured for attaching to a first tube (12) to deliverfluids to a patient. The first proximal outlet extends into at least aportion of the joined drip chamber. The drip chamber cap includes asecond distal inlet (14) configured for attaching to a second tube (16)connected to a source of the fluids (18) and a second proximal outlet(20) configured for dripping the fluids into the joined drip chamber. Asthe cross sectional area of the second proximal outlet decreases thenumber of drops per volume of fluid increases. For example, the numberof drops per mL could increase from 10 to 60 drops per mL if the crosssectional area of the second proximal outlet were to decrease. Theincoming fluid enters through the drip chamber cap, fills the joineddrip chamber to the fill line (60) and exits through the bottom. Thejoined drip chamber being spherical in shape, and having the firstproximal outlet at the bottom center of the joined drip chamber, ensuresthat the outlet is continuously submerged in fluid, thus removing airbubbles. The drip chamber assembly of the present invention prevents airfrom entering the fluids that are delivered to a patient irrespective ofthe orientation of the drip chamber assembly. This feature isparticularly valuable when there is no room and/or time to elevate thefluids or this not sufficient personnel present to hold the fluids overa patient.

Referring to FIG. 2, the ADPC includes a drip chamber top (44) whichconsists of two portions: approximately one-half of the sphericalportion of the all position drip chamber; and the neck portion which iscylindrical in shape and also acts as the primer pump in the device.This chamber can also have an oblong or polygonal shape to allow forsemi-equidistance from the perimeter to the center orifice, providingfor continuous immersion of the orifice within. The drip chamber topattaches to the drip chamber bottom (42) and the drip chamber cap (6).The drip chamber top can be made from a flexible plastic, but can besome other polymer or material depending upon the intended use; thiscould also be accomplished using semi-rigid materials, or a combinationof rigid and flexible materials. For example, for medical applications,the drip chamber top can be made from a medical grade flexible PVC, orsoft durometer polyurethane, or any flexible thermoplastic approved forthe intended application. A flexible top allows for this portion to besqueezed and function as a priming pump for the liquid that flowsthrough the drip chamber, and/or to assist in purging air from the line;if not intended for medical use the chamber could have a sealable ventto allow for purging air or gasses, via a manual or automatic method.

As mentioned above, another feature of the drip chamber top is a raisedfill line (60) indicator. This raised fill line enables the operator ofthe device to physically feel the level to which the chamber is filled.This feature is particularly useful when visibility is low and theoperator is in a high pressure hectic situation.

Yet another feature of the drip chamber top is a circular male member(46) located in the lower portion of the drip chamber top. The malemember of the interlocking design is further illustrated in FIG. 3. Thisfeature locks the drip chamber top and bottom together such that whenpressure is applied to the neck portion (48) the top and bottom will notseparate causing leakage.

The drip chamber bottom (42) forms the approximately other half of theADPC. The drip chamber bottom attaches to the drip chamber top and isone-half to two-thirds spherical, or oblong, or polygonal in shape. Formedical applications, the drip chamber bottom can be made from a medicalgrade acrylic, or any suitable hard plastic or polyurethane. The bottomcan be machined from plastic or metal.

A feature of the drip chamber bottom is that it has an exit passage onthe center of the sphere that enables the operator of the device to usethe chamber in any position while maintaining the exit passage fullysubmerged in fluid. Another feature of the drip chamber bottom is thefemale member (70) (FIG. 3), which includes an outer (72) and innercircular portion (74), that are located in the upper portion of the dripchamber bottom. The circular female portion (46) is positioned betweenthe circular outer (72) and inner (74) portions of the female member(46). This feature is critical for locking the drip chamber top andbottom together in a way that when pressure is applied to the neckportion the top and bottom will not separate causing leakage.

The drip chamber top and bottom can be produced by any type ofmolding/casting/machining process that can achieve a usable part thatinterfaces properly with its mating components. These processes include,but are not limited to, injection molding, polyurethane casting,silicone molding, or Soft Cast TPU (thermoplastic polyurethane) methods.

Referring to FIG. 4, in another embodiment, the drip chamber assemblycan be used with a cuff (30) to hold the source of the fluids (112). Acarbon dioxide or other gas cartridge (32) can be used to pressurize thecuff, which pressures the source of the fluids to provide for rapidinfusion. The fluid bag is inserted into the cuff, which is inflated,putting pressure on the contents of the IV bag.

The APDC assembly may be put together by attaching the drip chamber topto the drip chamber bottom with the mating areas being the troughinterface design discussed above. The parts can be attached usingvarious methods including, but not limited to, solvent bond, ultraviolet(UV) activated glue, sonic welding, over molding, spin welding, andchemical bonding.

The drip chamber cap (6) (FIG. 1) is connected to the APDC top bycreating a “slip fit” between the cap and the cylindrical/neck portionof the top. Once this fit is achieved the two components are bondedtogether further. Bonding methods can include, but not limited to,gluing, ultra violet light-cured bonding, overmolding, or any othersecondary process by which two dissimilar plastics can bond together toprevent leaks. There is no glue in the orifice in the center of the dripchamber bottom or cap.

Pressure Testing

In order to determine if there is an air leak in the drip cup assembly,including its attached tubing, testing can be performed by firstverifying an air pressure of 50 kpa (or some other designated pressure)on a pressure gauge. Referring to FIG. 5 and FIG. 6, the cap (50) isremoved from the spike (52), and the vented female cap (108) is removedfrom the male luer lock (110) (FIG. 6). The spike and male luer lock areinserted into ports of a testing fixture. The air eliminating filter or“aquaphobic filter” (100) is placed in between the clamps (40, 102) andclamp IV tubing, and the pressure is turned on. The APDC top is squeezedat both glue lines (cap and bottom) to ensure no separation and propergluing while making sure proper pressure is being kept. Also, the rollerclamp (40) and slide clamp (102) are examined to make sure they are openand that injection ports (104), (106), (FIG. 6) are tight. The device istested to verify that it retains a pressure of 50±0.1 kpa.

APDC air leak testing is performed using a method similar to that usedin the tube assembly air leak testing. First, air pressure of 100 kpa(or some other designated pressure) on a pressure gauge is verified. TheAPDC is corrected to the spike attachment and to male luer lockattachment before the pressure is turned on. The APDC top is thensqueezed at both glue lines (cap and bottom) to ensure no separation andproper gluing while making sure proper pressure is being kept.Verification is done to make sure that the device retains a pressure of100±0.1 kpa.

Tube set assembly bubble leak testing can be performed by firstverifying an air pressure of 50 kpa (or some other designated pressure)on a pressure gauge. The cap is removed from the spike and the ventedfemale cap for male luer lock. The spike and male luer lock are theninserted into ports of a testing fixture. The tube on both sides of theair eliminating filter are clamped off. The device is immersed in awater bath where the pressure test is conducted. Air may only leak boutof the filter.

Tube set tensile testing can be performed by clamping the spike to aclean room ceiling and hanging a minimum of 15 N weight to the end oftube assembly for 15 seconds. Each possible joint on the tube assemblyis placed into the tensile tester and pulled until failure. Each jointtested can only break at least at 15N or higher.

Instructions for Use

To use the drip cup assembly of the present disclosure to deliver afluid, the second tube (12) is clamped with roller clamp (40) 6 to 8inches below bottom of drip chamber shown in FIG. 1. The cover (50) isremoved from the spike (52) (FIG. 5). The spike is inserted into thesource of the fluids. The source of the fluids can then be inserted intothe cuff (30) (FIG. 4). The pressure infuser (32) (FIG. 4) is thenactivated by screwing the cap that contains the CO₂ cartridge clockwiseuntil the cartridge is punctured expelling the gas into the expansionchamber. The roller clamp is released while inverting the drip chamberbottom. The drip chamber is allowed to fill to the indicated fill line(111) and then may be orientated to any position to function properly.The fluids entering the chamber are allowed to reach the fill line. Theroller clamp is reclamped adjusting for the desired flow rate.

Inside the drip chamber, fluid should be visible dripping down from theIV bag into the tubing so that the speed of a manual IV setup can bemeasured. An attendant can view the chamber and count the number ofdrops per minute. For example, if 25 drops fell over the period of 60seconds, the IV would be infusing at a rate of 25 drops per minute, or25 gtt/min. Counting can be done for less than a minute to extrapolatethe number of drops that would fall in a full minute.

The drip chamber in use should contain fluid to the raised fill line(111) (FIG. 6). This is because if the drip chamber is too full, thedrops will not be visible to count and the IV infusing rate cannot bedetermined, and if the drip chamber is not full enough, then air canenter into the IV tubing. From the tubing air could get into thepatient's circulatory system (if the device is being used for IVdelivery), which could potentially block a blood vessel or stop theheart.

Most IV medication or other fluids are ordered to infuse or deliver at aspecific rate. Thus, the assembly is set up so that it infuses ordelivers at this specific rate and to adjust the IV periodically if theactual rate deviates from the ordered rate. The rate at which a fluidinfuses is referred to as the “IV infusion rate” or “flow rate.” Theroller clamp (40) (FIG. and FIG. 6) is the mechanism to control the rateat which the IV fluid infuses. If the roller clamp is rolled in aparticular direction, it squeezes the IV tubing more tightly, making itnarrower and therefore restricting the fluid flow through the tubing.And if the roller clamp is rolled in the opposite direction, it loosensits pinching of the IV tubing, making the tubing less narrow, andallowing the IV fluid to flow through at a faster rate. All rollerclamps on a set of IV tubing should be closed before attaching a bag ofIV fluid to the top of the tubing in order to ensure that no air getsinto the tubing. The slide clamp (102) (FIG. 6) is used to completelystop the IV from flowing, without having to adjust the roller clamp.This feature is particularly useful if it is desired to momentarily stopthe IV without having to readjust the roller clamp to its previoussettings. The side clamp works by pinching the tubing completely shutwhen the tubing is slid into the narrowest part of the side clamp.Additional IV medication(s) can be delivered to a patient by methodsthat include, but are not limited to, adding the medications into theoriginal IV bag and introducing the medications via the male luer lockinjection site (104) and luer activated Y connector (106) disclosed inFIG. 6.

Alternatively or additionally, an injection port can be used to injectmedicine or fluids other than those in the current IV bag into thepatient's vein through the IV tubing. An injection port is a means bywhich medicine or fluids other than those in the IV bag can be injectedor administered such that they will infuse into the patient's vein (orinto a target device) through the IV tubing. There are two possible portsites: one on the IV bag, itself (12) (FIG. 4) and one below the dripchamber (104) (FIG. 6). There may also be an injection port (106) FIG. 6close to where the needle goes into the patient's vein. The injectionport on the IV bag is used if medication mixing with the fluid in the IVbag is required. If the medication is injected into this port and thebag “rolled” to mix the medication with the fluid in the bag, then thepatient will receive both the medication and the IV fluid simultaneouslyat the allocated drip rate. A second medication or fluid can be injecteddirectly via injection port (106) (FIG. 6) so that it is not dilutedwith the IV fluid, then one of the ports that is located below the dripchamber is used.

EQUIVALENTS

Those skilled in the art will recognize, or be able to ascertain, usingno more than routine experimentation, numerous equivalents to thespecific embodiments described specifically herein. Such equivalents areintended to be encompassed in the scope of the following claims.

1-3. (canceled)
 4. A drip chamber, comprising: a substantiallyhemispherical drip chamber top including a squeezable material andhaving an upper portion defining a chamber inlet and a lower portionhaving a circular male member; a neck portion extending outward from anouter surface of the substantially hemispherical drip chamber top anddefining a neck inlet, such that the neck inlet is in fluidcommunication with the chamber inlet; and a substantially hemisphericaldrip chamber bottom including a rigid material and having an lowerportion defining an outlet and an upper portion having a circular femaleelement that has a complementary shape to the male member of thesubstantially hemispherical drip chamber top.
 5. The drip chamber ofclaim 4, wherein the substantially hemispherical drip chamber topincludes a soft polymer.
 6. The drip chamber of claim 5, wherein thesubstantially hemispherical drip chamber top includes at least one offlexible PVC, silicone, or soft durometer polyurethane.
 7. The dripchamber of claim 4, wherein the substantially hemispherical drip chamberbottom includes a rigid polymer.
 8. The drip chamber of claim 7, whereinthe substantially hemispherical drip chamber bottom includes acrylic. 9.The drip chamber of claim 4, wherein the substantially hemisphericaldrip chamber top is bonded to the substantially hemispherical dripchamber bottom.
 10. The drip chamber of claim 9, wherein the circularmale member of the substantially hemispherical drip chamber top isbonded inside the circular female portion of the substantiallyhemispherical drip chamber bottom.
 11. The drip chamber of claim 4,wherein the neck portion is cylindrical.
 12. The drip chamber of claim4, wherein the substantially hemispherical drip chamber top isconfigured to prime pump fluid into the drip chamber.
 13. The dripchamber of claim 4, further comprising a cap positioned inside the neckinlet.
 14. The drip chamber of claim 13, wherein the cap has a slip fitwith the neck inlet.
 15. The drip chamber of claim 14, furthercomprising a tube connected to the cap.
 16. The drip chamber of claim 4,further comprising a source of fluids in fluid communication with theneck inlet.
 17. A drip chamber of claim, comprising: a substantiallyhemispherical drip chamber top having an upper portion defining achamber inlet and a lower portion, the substantially hemispherical dripchamber top including a fill line; a neck portion extending outward froman outer surface of the substantially hemispherical drip chamber top anddefining a neck inlet, such that the neck inlet is in fluidcommunication with the chamber inlet; and a substantially hemisphericaldrip chamber bottom having an lower portion defining an outlet and anupper portion having a circular female portion that has a complementaryshape to the male member of the substantially hemispherical drip chambertop.
 18. The drip chamber of claim 17, wherein the fill line is raisedoutwardly relative to the outer surface of the hemispherical dripchamber top or inwardly relative to an inner surface of thehemispherical drip chamber top.
 19. The drip chamber of claim 17,wherein the fill line encircles the hemispherical drip chamber top. 20.The drip chamber of claim 17, wherein hemispherical drip chamber topincludes squeezable material.
 21. A method of supplying fluids into abody, the method comprising: supplying the fluids into a drip chamberthat includes: a substantially hemispherical drip chamber top includinga squeezable material and having an upper portion defining a chamberinlet and a lower portion having a circular male member; a neck portionextending outward from an outer surface of the substantiallyhemispherical drip chamber top and defining a neck inlet, such that theneck inlet is in fluid communication with the chamber inlet; and asubstantially hemispherical drip chamber bottom including a rigidmaterial and having an lower portion defining an outlet and an upperportion having a circular female portion that has complementary shape tothe male member of the substantially hemispherical drip chamber top; andsupplying the fluids from the drip chamber into the body.
 22. The methodof claim 21, further comprising priming the fluid into the drip chamberby squeezing the substantially hemispherical drip chamber top.